In City of Houston v. First City National Bank, 827 S.W.2d 462, 479 (Tex. App.--Houston 1st Dist. 1992, writ denied) the Court addressed the issue of whether counsel for various taxing units was liable for attorney fees incurred by a taxpayer in a suit to force the taxing units to comply with terms of an agreement. The Court held that tax collection activity by a city or school district is a governmental, and not a proprietary, function, "and the mere fact that the tax collection function has been assigned to a private law firm does not change the nature of the function from governmental to proprietary." Id. at 480. The Court also observed that section 101.055 of the Texas Tort Claims Act (TTCA) was intended "to insure immunity to the taxing unit while performing the governmental function of collecting revenue." Id. at 481. Therefore, "imposing personal liability upon the taxing unit's agent while performing this governmental function would be contrary to public policy." Id. The Court also addressed the nature of the liability of an agent. The Court discussed the established rule "that where an agent acts on behalf of a disclosed principal . . . within the scope of the authority conferred on him, it will not ordinarily be personally liable to the other party to the contract, in the absence of an agreement to the contrary or other circumstances showing that he has, either expressly or impliedly, assumed such liability." Id. at 480. The Court stated that the only exceptions to the general rule that "in a legitimate transaction, an agent is ordinarily liable only to his principal" occur when (1) the agent contracts in his own name, (2) the principal is undisclosed, (3) the agent is authorized to act as the owner of the property, or (4) the agent has an interest in the subject matter of the contract. Id.